<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <div id="root"></div>

    <script src="https://unpkg.com/react@17.0.2/umd/react.development.js"></script>
    <script src="https://unpkg.com/react-dom@17.0.2/umd/react-dom.development.js"></script>
    <script src="https://unpkg.com/@babel/standalone/babel.min.js"></script>
    <script type="text/babel">
        // 创建组件
        class Weather extends React.Component {
            // 构造调用了几次？ 1次
            constructor() {
                super()

                this.state = {
                    isHot: true
                }
            }

            // render调用了几次？ n+1次
            render() {
                console.log(this)
                return (
                    <h2 onClick={() => this.changeWeather()}>今天的天气很{this.state.isHot ? '炎热' : '凉爽'}</h2>
                )
            }

            changeWeather() {
                this.setState({
                    isHot: !this.state.isHot
                })
            }
        }

        ReactDOM.render(<Weather />, document.getElementById('root'))
    </script>
</body>
</html>